diff --git a/features/storage/filesystem/fat/FATFileSystem.cpp b/features/storage/filesystem/fat/FATFileSystem.cpp
index 12b3d0871e..90229131f2 100644
--- a/features/storage/filesystem/fat/FATFileSystem.cpp
+++ b/features/storage/filesystem/fat/FATFileSystem.cpp
@@ -1,5 +1,5 @@
 /* mbed Microcontroller Library
- * Copyright (c) 2006-2012 ARM Limited
+ * Copyright (c) 2006-2019 ARM Limited
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -280,9 +280,8 @@ extern "C" DRESULT disk_ioctl(BYTE pdrv, BYTE cmd, void *buff)
 
 // Filesystem implementation (See FATFilySystem.h)
 FATFileSystem::FATFileSystem(const char *name, BlockDevice *bd)
-    : FileSystem(name), _id(-1)
+    : FileSystem(name), _fs(), _id(-1)
 {
-    _fs = { 0 };
     if (bd) {
         mount(bd);
     }